fix some typos in the tutorial

doc/source/tutorial/tutorial1.rst

@@ -302,7 +302,7 @@ generator that iterates over all points in the rectangle as did the
 two ``for``-loops in the previous example. In fact, a
 `~kwant.builder.Builder` can not only be indexed by a single
 lattice point -- it also allows for lists of points, or, as in this
-example, an generator (as is also used in list comprehensions in
+example, a generator (as is also used in list comprehensions in
 python).
 
 Having added all lattice points in one line, we now turn to the
@@ -415,7 +415,7 @@ The result of the example should be identical to the previous one.
 
      For technical reasons it is not possible to add several points
      using a tuple of sites. Hence it is worth noting
-     the a subtle detail in
+     a subtle detail in
 
      .. literalinclude:: ../../../examples/tutorial1b.py
          :lines: 27

doc/source/tutorial/tutorial2.rst

@@ -66,7 +66,7 @@ the hoppings in the form expected by
   hopping from `(i, j)` to `(i+1, j)`, whereas `(1, 1)` would
   mean hopping to `(i+1, j+1)`.
 - The target lattice (where to hop to)
-- The source lattice (where the hopping originates
+- The source lattice (where the hopping originates)
 
 Since we are only dealing with a single lattice here, source and target
 lattice are identical, but still must be specified  (for an example
@@ -315,7 +315,7 @@ Up to now, the system contains constant hoppings and onsite energies,
 and we still need to include the phase shift due to the magnetic flux.
 This is done by **overwriting** the values of hoppings in x-direction
 along the branch cut in the lower arm of the ring. For this we select
-all hoppings in x-drection that are of the form `((1, j), (0, j))`
+all hoppings in x-direction that are of the form `((1, j), (0, j))`
 with ``j<0``:
 
 .. literalinclude:: ../../../examples/tutorial2c.py

doc/source/tutorial/tutorial3.rst

@@ -48,7 +48,7 @@ Hamiltonian is approximating.
 
   - Note that we have used `~kwant.system.InfiniteSystem.energies` as if it
     were a function. In fact, `~kwant.system.InfiniteSystem.energies` is a
-    so-called callable object, i.e. a object that can be used just as a
+    so-called callable object, i.e. an object that can be used just as a
     function. We could also have written::
 
         Energies = flead.energies
@@ -103,7 +103,11 @@ want to use sparse matrix methods.) Finally, we obtain the result:
 At zero magnetic field several energy levels are degenerate (since our
 quantum dot is rather symmetric). These degeneracies are split
 by the magnetic field, and the eigenenergies flow towards the
-Landau level energies at higher magnetic fields [#]_
+Landau level energies at higher magnetic fields [#]
+
+.. seealso::
+    The full source code can be found in
+    :download:`examples/tutorial3b.py <../../../examples/tutorial3b.py>`
 
 .. specialnote:: Technical details
 

doc/source/tutorial/tutorial4.rst

@@ -9,9 +9,8 @@ and two non-collinear leads. In the process, we will touch
 all of the topics that we have seen in the previous tutorials,
 but now for the honeycomb lattice. As you will see, everything
 carries over nicely.
-spectrum of a quantum dot.
 
-We begin from defining the honeycomb lattice of graphene. This is
+We begin by defining the honeycomb lattice of graphene. This is
 in principle already done in `kwant.lattice.Honeycomb`, but we do it
 explicitly here to show how to define a new lattice:
 
@@ -70,7 +69,7 @@ as add an additional link:
     :lines: 55-56
 
 Note that the conversion from a tuple `(i,j)` to site
-is done be the sublattices `a` and `b`.
+is done by the sublattices `a` and `b`.
 
 Later, we will compute some eigenvalues of the closed
 scattering region without leads. For that, obtain a finalized
@@ -115,7 +114,7 @@ plot the system:
     :lines: 135-137, 142-147
 
 Here we customize the plotting: `plotter_symbols` is a dictionary
-which the sublattice objects `a` and `b` as keys, and the
+with the sublattice objects `a` and `b` as keys, and the
 `~kwant.plotter.Circle` objects specify that the sublattice `a` should
 be drawn using a filled black circle, and `b` using a white circle
 with a black outline. The radius of the circle is given in relative
@@ -128,7 +127,7 @@ length scale using the argument `a` as in the example (not to be
 confused with the sublattice `a`) which is here set to the distance
 between carbon atoms in the graphene lattice. Specifying ``r=0.3`` in
 `~kwant.plotter.Circle` hence means that the radius of the circle is
-30% of the carbon-carbon distance. Using this relative units it is
+30% of the carbon-carbon distance. Using this relative unit it is
 easy to make good-looking plots where the symbols cover a well-defined
 part of the plot.
 
@@ -178,7 +177,7 @@ an open quantum dot
    :func:`plot <kwant.plotter.plot>` for more details.
 
  - In a lattice with more than one basis atom, you can always act either
-   on all sublattice at the same time, or on a single sublattice only.
+   on all sublattices at the same time, or on a single sublattice only.
 
    For example, you can add lattice points for all sublattices in the
    current example using::